1. Field of the Invention
The invention teaches and claims a navigational instrument suitable for marine ship celestial navigation on a large body of water. The invention is classified in Class 33 Subclasses 75 and 76.
2. Description of the Prior Art
C. Freda, in U.S. Pat. No. 3,393,457 issued July 23, 1968, discloses a chart board having a frame with a large diameter opening found therein and a course protractor supported in the opening. The protractor includes an outer graduated ring rotatably supported in the opening and an inner ring member supported in the opening by the outer ring member.
In U.S. Pat. No. 2,216,490 issued Oct. 1, 1940, R. V. Garret disclosed and claimed an aircraft navigational instrument adapted to directional navigation from radio stations of known location. A plate has indicia thereon suitable for aligning the plate with map meridian lines, a first means rotatable with respect to the plate for compensating for compass deviation from true north, a second means rotatable with respect to the first means for indicating an aircraft's compass heading, and a pair of slotted discs, each having a plurality of parallel slots therein. The pair of slotted discs are rotatable with respect to each other. The pair of discs are adapted to indicate on the above second means the directions to points of known positions.
H. M. Jensen, in U.S. Pat. No. 2,004,951 issued June 18, 1935, discloses and claims a navigational instrument for aircraft, having a head and stern portions, together with a compass rose secured in an aperture in the head portion.